Katselli Proukaki, Elena, author
Routledge, 2010
Buku Teks
Rodgers, William H., author
St. Paul Minn, 1977
Buku Teks
Schwartz, Bernard, author
Little, Brown & Co., 1991
Buku Teks
Rodgers, William H., author
West Publishing, 1994
Buku Teks
Schwartz, Bernard, author
Little, Brown & Co., 1976
Buku Teks